1. Field
This disclosure relates generally to semiconductors, and more specifically, to through vias used in semiconductors.
2. Related Art
The use of through vias, which are vias that pass through a substrate and are also known as through substrate vias (TSVs), have come into more common usage. Many difficulties, however, remain. One continuing problem is sufficiently filling the through via without forming voids. This is a difficult issue due to the relatively long distance the through via must traverse in going from one side of a substrate to the other side. Further, there are issues relating to compatibility with preferred materials used for front end processes. Copper is commonly used for interconnect but use for vias, especially in contacting silicides, has provided problems. Even though many deposition problems with plating copper have been overcome, copper has not been found to be effective for through vias due in part with incompatibility with the contact materials used for contacting silicides. Also plating can be difficult in a via that is very small or has a high aspect ratio.
Thus, there is a need for a technique that provides through vias that improve upon one or more of the issues raised above.